Also see the same filing for the planned IQ Innovation Leaders ETF, which would be based on factors like R&D expenses versus total assets and capital expenditures versus total assets.

Yes, we’re a long way from the SPDR S&P 500 ETF (SPY) with these ideas, and we’ll see whether the ETF market’s niche-building phase pleases an equally niche-y number of investors, or more. The brief life and merciful death in recent years of funds for fishing stocks, etc., is suggestive.

The trend toward niches isn’t going way, and may even intensify. This year already we’ve gotten the market’s first Forensic Accounting ETF (FLAG), a business-development company ETF and the umpteenth slices of master-limited partnerships. Last year brought ETFs like the socially minded AdvisorShares Global Echo ETF (GIVE) and the hedge-fund-stock-pick-inspired AlphaClone Alternative Alpha ETF (ALFA).

About Focus on Funds

As exchange-traded funds and other investing vehicles have ballooned in number, the task of figuring out what works well and what doesn’t has only gotten harder. Barrons.com’s Focus on Funds looks under the hood of ETFs, mutual funds and hedge funds for overlooked values, actionable ideas and the latest pitfalls for fund investors.

Chris Dieterich has covered the U.S. stock market for The Wall Street Journal and Dow Jones Newswires. He is a graduate of Regis University and the Missouri School of Journalism.